The invention relates to a method of and to an apparatus for determining or ascertaining the mass or weight of rod-shaped articles of the tobacco processing industry, particularly of wrapped sections of rod-like tobacco fillers of predetermined (unit or multiple unit) length.
The weight or mass (hereinafter referred to as weight) of cigarettes, cigarillos or other rod-shaped articles of the tobacco industry is being ascertained in a number of ways. The presently most popular procedure involves the measurement of density with beta rays. Thus, a wrapped rod-like tobacco filler is caused to advance along a predetermined path and across one or more beams of beta radiation. The intensity of radiation which has penetrated across the moving wrapped filler is determined and the thus obtained signals are indicative of the density of the respective increments of the monitored filler. These signals can be processed to denote the weight of discrete rod-shaped articles which are obtained by causing the filler to advance through a so-called cutoff or another severing device downstream of the density monitoring station. The just outlined procedure can be resorted to in order to ascertain the weight of rod-shaped articles of unit length or multiple unit length. Such procedure can furnish reasonably acceptable (accurate) results up to a certain limit. Thus, as the rate of monitoring increases above a predetermined value and the intensity of radiation remains unchanged, the accuracy of measurement deteriorates considerably. Moreover, the utilization of radiactive material for the determination of density contributes to the cost and complexity of the entire production line in order to ensure absolute safety for the attendants. In fact, many makers of rod-shaped articles of the tobacco processing industry, and even the ultimate consumers, are reluctant to utilize equipment or to buy products the density (and thereupon the weight) of which was determined by resorting to beta rays.
Another known proposal involves the utilization of optical radiation in the infrared range of the spectrum of electromagnetic waves. This eliminates the problems involving the safety of the testing equipment but creates other serious problems, particularly how to eliminate or how to compensate for the undesirable influence of certain characteristics of the contents of rod-shaped articles of the tobacco processing industry upon the intensity of optical radiation which is caused to impinge upon successive increments of a rapidly advancing rod and issues from the rod to be utilized as an indicator of the density of corresponding increments of the rod. Therefore, such optical measurements failed to gain widespread acceptance in the industry because the elimination of or compensation for all of the undesirable influences contributes significantly to the initial and maintenance cost of such equipment.
Still another known proposal involves actual weighing of batches of rod-shaped articles which are withdrawn from their path in a production line. The withdrawn articles can be weighed individually or in groups of two or more. This mode of weight determination is highly satisfactory as concerns the actually weighed articles but is not acceptable in many instances, e.g., when it is desirable or necessary to ascertain the weight of each and every rod-shaped article in a machine which turns out such articles at an extremely high rate.